Heretofore, various processes for producing a polysaccharide utilizing microorganism have been proposed. However, the greater part of these processes was concerned with a viscid polysaccharide and there have been very few reports concerning a process for the production of a polysaccharide forming a gel. In addition, the known polysaccharides characterized by gel-formation have been produced by utilizing sugars as the carbon source of a nutrient medium.